diff --git a/contains-duplicate/hajunyoo.py b/contains-duplicate/hajunyoo.py
new file mode 100644
index 000000000..ded649695
--- /dev/null
+++ b/contains-duplicate/hajunyoo.py
@@ -0,0 +1,6 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        string_len = len(nums)
+        set_len = len(set(nums))
+
+        return string_len != set_len
\ No newline at end of file